I got a schema for products. I want to be able to query them and sort on discount. The price is represented with an array called price, the latest element is the newest value. I.e I want the product with the highest discount first in the query.
Schema:
const mongoose = require('mongoose');
const ProductsSchema = new mongoose.Schema(
{
productName: {
type: String,
},
price: [
{
date: {
type: String,
},
value: {
type: Number,
},
},
],
},
{ collection: 'products' }
);
const products = mongoose.model('products', ProductsSchema);
module.exports = products;
Query1
aggregate(
[{"$set":
{"discount":
{"$cond":
[{"$lte":[{"$size":"$price"}, 1]}, 0,
{"$subtract":
[{"$last":"$price.value"},
{"$arrayElemAt":
["$price.value", {"$subtract":
[{"$size":"$price"}, 2]}]}]}]}}},
{"$sort":{"discount":-1}}])
Query2
*you can replace $last with $max to get the max discount of all time
aggregate(
[{"$set":
{"discount":
{"$cond":
[{"$lte":[{"$size":"$price"}, 1]}, 0,
{"$subtract":
[{"$last":"$price.value"}, {"$min":"$price.value"}]}]}}},
{"$sort":{"discount":-1}}])